The invention relates to a guide device and method for the backlash-free alignment of mutually relatively displaceable parts of an optical instrument.
Optical instruments, in particular microscopes or their object stages, are moved for focusing purposes via a rack-and-pinion housing along a fixed profile column. In relation to the displacement on the profile column, very high demands are made for the precise alignment of the guide elements and the precise compliance with this direction of movement. In order to guarantee this, highly accurate axial or radial guides having sliding or rolling members are used between the profile column and the rack-and-pinion housing. However, these guide elements place very stringent requirements on the manufacturing accuracy of the individual components over the entire length of the profile column. An adjustment of the guide elements is indispensable in order to compensate existing inaccuracies in the guide tracks.
DE-C 469 955 discloses an elastically constructed tubular guide for a microscope, in which coil springs are used to press the sliding surface of a guide rod against the sliding surface of a guide block in such a way that there is a constant pressure against the respective sliding surfaces.
DE-B 19 24 400 and FR 2 207 550 disclose mechanical guide elements in which two parts which can move against one another and between which roller bearings are arranged are adjusted by springs. After adjustment is performed, the spring action is canceled by sealing cavities by means of a casting resin.
DE-C 1 051 025 discloses a backlash-compensating device for setting optical instruments which has two parts arranged movably relative to one another. The parts which can move relative to one another are supported by bearings which are designed with a plastic insert which can be elastically compressed. The strip-shaped plastic inserts are located partially in one groove each and form the sliding bearing surfaces with their parts which project over the groove.
In the case of assembly, such plastic inserts of fixed thickness have the disadvantage that backlash compensation is possible only in very narrow tolerances or that a multiplicity of different material thicknesses must be made available.